<!DOCTYPE html>
<html>
<head>
  <title>Painting deep tree with CSS Blending</title>
  <!-- https://codereview.chromium.org/478333002/ -->
  <style>
    .box {
      width: 100px;
      height: 100px;
      position: relative;
      z-index: 1;
      top: 10px;
      background-color: green;
      border: 1px black solid;
    }
    .blending {
      mix-blend-mode: difference;
    }
    .container {
      position: absolute;
      left: 0px;
      z-index: 0;
    }
  </style>
  <script>
    window.onload = function() {
      var container = document.createElement('div');
      container.classList.add('container');
      var lastElement = container;
      for (var i = 0; i < 100; i++) {
        var box = document.createElement('div');
        box.classList.add('box');
        lastElement.appendChild(box);
        lastElement = box;
      }
      // The leaf element has blending.
      lastElement.classList.add('blending');
      document.body.appendChild(container);
      // Force repaint.
      var left = 0;
      (function frame() {
        container.style.left = left + 'px';
        left = (left + 1) % 2;
        requestAnimationFrame(frame);
      })();
    };
  </script>
</head>
<body>
</body>
</html>
